Radio telephone and telegraph circuits



2 Sheets-Sheet l k.) INVENTORS ATTORNEY J. HERMAN ET AL RADIO TELEPHONE.AND TELEGRAPH CIRCUITS Filed Feb. 5. 1929 Feb. 2, 1932.

Feb. 2, 1932. .1. HERMAN ET AL 1,843,228

RADIO TELEPHONE AND TELEGRAPH CIRCUITS ZIE . 2, Camif/'00 Raw/7@ 'r @ggv INVENToRs .Igel/Www, EzyZa/f @L Wsw@ , ATTORNEY Patented Feb. 2, 1932UNIT-E srarns vrarenr orricn kJOSEPH HERMAN, OE wEsTEiEEn, NEW JERSEY,EDMUND n. TAYLOR, OE NEW YORK, N. Y., AND sUMNEnnwnien'r, OE souri-Ionsite-E, NEw JEnsEY, nssrenons ro AMEnrcAN TELEPHONE AND Tanne-nnencontraria?, A conronn'rron or NEW lYORK RAD TELEPHONE .AND TELEGRLHCIRCUITS yllqiplication filed February 5, i829. Serial No. 837,616.

Vtelegraph messages over a radio telephone channel. p

' ln o1 eratin' aradio tele yhone circuit such Vas the transatlanticsystem between the United States and Great Britain it is desirable totransmit iniormation for setting up telephone callsby means of yprintingtelegraphy. A irinter is also desirablei'for sending information betweentechnical employees having` charge of themaintenance of the circuit. Inaccordance with the present invention, circuit arrangements are provided'whereby printer messages may be transmitted Vduring times that theradio link is not being employed for telephone transmission.

As is well lnowina radio transmitter and radi-o receiver may' beconnected by means of a four-wire circuit at Rocky Point, Long island,and the receiver at Houlton, iti-aine, while the switching point is inNew York City. 'The'our-wire circuit compri es two two-wire linesextending from New Yori City to Rocky Point and froulton, respectively.ln the ciiice at N ew Yorlr City, acontrol room is provided whereby atechnical operator has control ot the terminal amplifiers,voice-operated devices, privacy mechanism and other apparatus associatedwith the lfour-wire circuit. The two-wire terminal of the four-wirecircuit passes through the control room to an operating roomA where itterminates upon a ack so that the trar''ic operator may establishconnections to other telephone circuits. ln accordance with theinvention, printing apparatus is provided beth in the controlv room andin the operating room, so that either the technical operator'.orthetratiic Operator, atone end of the system, can communicate Vwiththe correspond- Ving loperators at the other end.A

Since the trahie operator is not ordinarily trained lto operate aVprinter, and more-over,

co a two-wire terminal at afswitching ypoint where connections areestabished between the'radio channel and various telephone circuits.Forexample, in f H5 vthe transatlantic radio telephone system abovekreferred' to, ythe radio transmitter` is located duties in connectionwith the establishi 'nt of connections which make it undesirafto burdenher with printer operation, the

printer in the Operating room is operated by a printer operator who islocated near the traiic operator, so that information relating io calismay be readily passed by the trailic operator to the printer' operatorfor transmission over the circuit.

ne printing equipment in both control and .sing rooms consists of twounits, one of l is a combined sending and receiving iter, and the oherof which is a receiv- `die two rooms y are connected serially in a loop,and likewise, the combined sending and receiving printer units of thetwo rooms are connected in another loop. The receiving "nter units areused when the system is opf ed on a full duplex basis with signals ,vsent in both directions at the same time.

ns, is used as a home recorder for recording tl e transmitted message.When operating on a half duplex basis, so that signals are transmittedonly in one direction at a given time, the receiving printer unit is notused, but the combined sending and receiving unit is used for bothsending and receiving in the local loop.

In the control room, the two loops are associated with a voice frequencycarrier arrangement soY that the printer messages may be sent andreceived over the four-wire circuit of the radio system by means of anaudible tone. rlhe receiving carrier channel is permanently bridgedacross the receiving path of the four-wire circuit between the radioreceiver and the echo suppressor disabling device, so lthat it is alwaysin condition to receive printer messages without any switchingoperation. The transmitting channel of the voice frequency carrierapparatus, on the other hand, i arranged to terminate in the operatingroom in a jack before the switchboard operator in the same manner thattelephone lines terminate, so that the sending printer may bc connectedto the twopath is disabled, the circuit is in condition 'to receivetelegraphmessages.' Means are also provided whereby, when the sendingwire terminal vot the tour-wire system by means of the operators cordcircuit.

Arrangements are provided so that when the sending printer vis connectedto the twowire terminal of the tour-wire system bythe cord circuit, thevoice-'operated echo suppressor equipment is automatically set to renderthe transmitting path of the four-wire circuit operative'to transmitsignals to the radio" transmitter. The receiving path is at the sametime disabled, but as thel carrier telegraph channel isconnectedther'eto between the radio receiver and the point atv which theprinter is Connected to the four-wire circuit, the Oain ot the amplifierin the transmitting path is automaticallysetatthe desired value Y torprinter transmission.

Supervisory signals are provided whereby Y th'eprinter operator in thecontrol room may signal the trafiicloperatorto setup 'or take down theprinter connection and whereby the jtrahfic operator may signal theprinter operator that the connection isset up. lMonitorfing means arealso provided so that the trahie operator may monitor the circuit. `Thecir- VVVcuit isalso so arranged that when the tratiic operator desirestouse'the radio link for telephone purposes, the sending printer may bedisconnected andra signalV will be given* to the Aprinteroperator toindicate that i'act.

Tn :the control room, the technical operator .is provided with meanswhereby the printer located in that room may be connected to thetwo-wire terminal ot the tour-wire circuit the Aprinter operator whenthe printer iscongiie'ctezd. to the circuit. Y v The inventionma-y now,be more derstood trom the following description Y fully unwhen read inconnection with the accompanyiing drawings, Figures l and 2 of whichshow the circuitv arrangement for one terminal of a radio telephonesystem kembodying the invention, and F ig; 8 of which shows amodification ofv the voicejfrequency carrier telegraph apparatusemployed in connection with the system.

YReferring tothe drawingaFigs. l and 2 showvr the circuit yarrangementof a four-wire terminating arrangemeiitat one end of a radeley circuitDR.

dio telephone system, the radio` transmitter and receiver, however,being not illustrated. It will be understood, of course, that thearrangement at the distant terminal of the radio telephone system willybejsiiiiilar'to that illustrated. In consideringthedrawingsnt should benoted that the portion of the circuit shown in Fig. 2 is the apparatusassociated with the, Y

four-wire circuit leading to the radio transmitterand receiver rointhetwo-wire terminahwhile the apparatus shown in Fig. l comprises printersand associated circuit arrangements ior connecting them with thefour-wire circuit.v lt should alsobe noted that all ofthe apparatus tothe lett ot the vertical dotted line in Fig. l is apparatus locatedinthe operating room 'where the traffic operator sets up telephoneandprinter connections ywith the radio system. The apparatus to the rightof the dotted line in Fig. l

cal operator has supervisory'control Jfor the purpose otl maintainingthek apparatus in proper operating condition.

Referring to Fig. 2, L designates the twowire terminal of the tour-wirecircuit interconnecting the radiov transmitter and radio lreceiveratoneend of a radio telephone sys- The two-wire terminal L is connected tem.through a hybrid coil 10 to a transmitting path TL Aand receiving pathRL, the terminal L being vbalanced by asuitable network 3N. The pathv TLincludes ainpliiiers TA and .TA and a delay circuit- DT. Beyond these Yelements the pathv TL isV associated bym'eans .of al hybrid coilllwith-the privacy mechaynism PM,.oie well-lmown form, which performs thefunction ofrendering speech transmitted therethrough unintelligible.Atterpassing'throiigh the privacy mechanism PM,

the transmitting path continuesfover'theline TL including the amplifier"',to the distant radio transmitter.

The receiving path RL', incoming from .the radio receiver, is connectedto the neuj tral points of the hybrid `coil l1. Since the Y privacymechanism PM is balanced by a network PN', the connection of thereceiving path RL to the hybrid coil renders such path conjugate withVrespect to the transmitting path The receiving path, after passingthrough vthe privacy mechanism PM, continues over the circuit RL whichincludes receivingzamplifiers RA and RA, as well as Inv order that whentransmission is taking Vplace over either the transmitting orreceivingpath, the other path willbe disabled,

echo suppressor devices are associatedwith veach path.v The echoYsuppressor equipment associated with the transmitterl path TL comprisesan amplifier-detector unit TAD, orwell-knownV type, bridged across thepath .TL on the output side of the amplifier TA.

v 1185 and the apparatus indicated in Fig. 2 will be .located in thecontrol room where the techni- The output of the amplifier-detector unitTAD controls-through master relay 20 the relays'12,.13, 1d and 15 forperforming the switching operation incident to the blocking .ordisabling operations ivhereby telephone transmission is permitted onlyin one direction at a time. Normally, both sections TL and TL of thetransmitting path are disabled by the back contacts ot' relays 12 and 13which short-circuit the conductors. Since vthese tivo sections of thetransmitting path are interconnected through the privacy mechanism PM,and the two short circuits are applied on opposite sides of the privacymechanism, .transmission from the section TL to the sectionk TL cannotnormally'talre place `through the privacy mechanism. Blocking means,yycomprising transformer arrangements 16-17 and 18-19, are associatedwith .the receiving path sections RL and RL, re-

spectively. These disabling means comprise .transformer arrangementswhich are so connected as to be balanced when the contacts ofV relays 14and 15 are opened, thereby preventing transmission through the transformer arrangements. When the contacts of relays 14 and 15 are closed,however, the

transformer circuits, instead ot being balanced lare in eitectconnectedso as to be ar- 7. u LL. u n allel aiding, thereby permittingtransmission f to rtake place readily. Normally, relays 14 l and 15y(which are controlled by the aniplitierdetector TAD)Y are deenergized,so thatl the receiving path is unblocked to permit transmission to takeplace from the ra- .dio receiverA through the privacy mechanism v'to theterminal of the Wire circuit L. An

I amplifier-detector arrangement RAD is conscribed for telephonetransmission is as follows :V Telephone currents incoming'over thetivo-Wire circuit L pass through the hybrid coil and through theamplifier TA. Some Vof the energy enters the amplifier-detector unit TADand causes the relays 12, 13, 14 and to be energized. Relays 12 and 13remove the short circuits from the transmitting sections TLr and TL',While relays 14 and 15, byopening their contacts, cause the inission ofthe telephone currents until these operations have taken place, fitterWhich the telephone currents pass through the amplithe telephoneoperation of the circuit.

fier TA through the hybrid coil 11, thence through the privacy mechanismPM and then out through the amplifier TA and over the line section TL tothe radio transmitter. The amplifier-detector RAD associated With thereceiving path cannot be actuated to disturb the circuit condition nowexisting, because the receiving path is disabled in the manner alreadydescribed.

It, in the normal condition of the circuit,

t lephone signals are received over the line section RL from the radioreceiver, they pass through the amplifier RA and the transformerarrangements 16-17 to the midpoints of the hybrid coil 11 and thencethrough the privacy mechanism PM, through the ampliiier RA and throughthe vtransformer arrangements 18-19. Sonie of the received energyactuates the amplitier-detector RAD to cause the operation oi the relay20 which opens the circuit controlled by the ampliiier-detector unitTAD, thereby preventing energization of relays 12, 13, 14; and 15, sothatthe transmitting path is maintained disabled and the receiving pathremains unblocked so long as telephone currents are being received. Tnthe meantime, the telephone currents aie delayed in passing through thedelay network DR until the foi'eooineo erations take lace after WhichbEl 7 the telephone currents pass through the receiving amplifier RA tothe niidpoints ot the iybrid coil 10 and thence to the two-Wire terminalL.

The apparatus so tar described relates to The printing telegraphequipment, and the circuits whereby it is associated With the four- Wiretelephone circuit leading to the radio transmitter and receiver, willnowbe described. Referring to F ig. 1, it Will be seen that thetivo-Wire terminal of the telephone circuit passes through the controlroom and terminates in a jack J in the operating room,

whereby it may be connected through a cord;

circuit GC to jacks, such as TJ, associated with telephone lines, suchas L, for complet ing connections to telephone subscribers. At thesufitchboard of the traffic operator (which includes the jacks ofvarious telephone lines such as TJ) is a jack TCJ which is connectedover a circuit TCL to the transmitting equipment of a voice frequencycarrier telegraph apparatus shoivn Within the dotted rectangle at Thecircuit may therefore be connected by the trailic operator through thecord circuit C to the two-wire terminal L of the tour-Wire telephonecircuit to connect to the circuit the Iending equipment or the printingapparatus hereinafter described.

The printer apparatus located in the operating room for sending andreceiving printer messages necessary tor'the establishment of telephoneconnections bythe traiiic operator,

comprises two units, a `combined'transmitting and receiving unitconventionally indiwhereby the printer operator may signal the'traic'operator when a connection to the -radio circuit `is desired. Y

--Siniilar printer equipment is located in the control room i'or the useof the t-echnicaloperator 'in sending messages relating` to the'maintenance and operation ot the circuits.

.This equipment comprises a combined transmitting and'receiving unit TPanda unit RP. which comprises a receiving printer only. The receiverunits RP and RP, in the operating: and control rooms, respectively, areconnected in series in a receiving loop RPL.

The sending and receiving' halves of the combined'printers TP and TP inthe operating .and control rooms, respectively, are arranged in'serieswith each other, andthe two units are also connected Vin series in aloop TPL,

s'othat wheiia sender of the unit TP, for

example, is operated, the associated receiving printer of that unit willoperate as a Vhome recorder, and also the receiving portion vof the'unitTl? will'record the same rnes- Y sage inthe control room. vLikewise,when record the 'messageLl -inay be associated with the set'TP for' tapethe Vsender ot the unit TP is actuated, the receivingelement's of bothyprinter units will A. tap-e transmitter TS sending. g

.The voice `frequency carrierapparatus at X is shown connected tor'afull duplex operation so that transmission may take .place in bothdirections simultaneously. VThis carrier apparatus comprises a.transmitting` relay TR associated with the transmitting loop TPL andhaving its varmature arranged to short-.circuit the output Vcioscillator O, which Vgenerates va tone frequency vwhich will beinterrupted in accordance with the transmitted printer signals, andtransmitted through the transformer 30 and over thercircuit TCL andtwo-wireterminal'l/ to the transmitting path of the'tour-wire circuit.The receiving1 portion ot' the voice frequencyv carrierequipnientcomprises a receiving relay RR for transmit-tine the printer code totheloop RPL. The relay Rit-is controlled by an amthe voice frequencycarrier equipment is per- -inanently associated with the receivingsecalhier-detector unit D for am lit ine` and rectif in@ the receivedtone ltrom the distant -f transmitter. The',amplifier-detector Al) oftion RL of the four-wire circuit over a cirvcuit whichvincludes anamplifier RCAv Hhaving ahigh impedance input, so that the connection' ofthe circuit RCL to `the receiving' path RLadoesfnot introduce anymaterial loss for telephone transmission over the Apath RLT-RL. A iilterRCF fory selecting the tone employed in transmitting from the distantstation may also bel included between tfnleD circuit RCL-'and theamplifier-detector A f The printer apparatus in thecontrol room may alsoinclude a' tape sender TS connected in series with the transmittingkeyboard of the transmitting unit TPV', so that control room messagesmay be punched on the tape and allowed to accumulate until the technicaloperator has an opportunity to obtain control oi' the radio circuit forprinter transmission. The` printer apparatus in the control roomhasassociated therewith a signal 29 for indicating when the sendingapparatus of the control 4room printer isconnected to the twowireterminal L. Such vconnection may be established independently oftheftrafflc 0peiator by fnieans of an ordinary patching cord PC which.will interconnect jacks CBJ and CBJ', the one associated with thesending printer and the other associated with the tivo-wire terminal L.vWhen the patching connection is made, the transmitting side ot thevoice frequencycarrier apparatus is disconnected irom the circuit TCLleading to the-tratlicoperators board and is connected to the jack CBJ.1 r

The traihc operators cord circuit CC for .establishing telephoneconnections orsending printer connections, includes the usualsupervisory signal 27, splitting'key SK and monitering and talking keyTMK the latter, when ,thrown to the left,fbridging the operatorsreceiverl OR kacross the cord, and, when thrown to the'right, connectingboth the operators transniitterOT and receiver OR to a tone sourceinaybe connected to the cord i circuit for signaling the traicoperator atthe distant end.. The tratc operator is also `provided with a lamp 25 toindicate signals transmitted by the printer operators key BSK whentheprinteroperator requests the circuit. The traliic operator is alsoprovided with a key BLK by which lshe can cause the printer operatorslamp 28 to flash to indicate that thetraific operator wants the circuitJor a telephone connection. The traiiic operator also has at herboard ajack MJ, byk

means Yof which she may monitor on the re- Y ceiving printer circuitRCL, a lamp 27 being provided to indicate to the traflic operator thatthe printer circuit is set up so that she should monitor. A y

A polar relay PR is bridged across the two-- wire terminal L; ilVhenoperated, this relay f performs three functions'. Itsets the poten-ytiometer of the amplifier TA in the transmitting path. It operatestherelays 12, '13, 14 and l5, to disable the receiving pathy and cutging into the jack MJ with another cord circuit, and'throwing amonitoring key. Another circuit is established throughthe relay K whichyshortcircuits the sending apparatus of the'control room printing set TPto prevent the 'sending' of printersignals Jfrom this set. A thirdcircuitl is established over the back contact of relay H to the lamp Q8associated withthe printing apparatus lin the ing marginal, was not;energized over the sleevecircuit, and hence thesupervisory ref lay U orthe cord was permitted to close the circuit of the supervisory lamp 26.As soon as relay C is energized, ground is connected over its upper'front contact lto short-circuit the 'resistance r, thereby increasingthe'cur'r rent iiow over the sleeve circuit through the relay l) andtheVv relay M, causing the latter to be energiZed,-thereby opening theVcircuit of thesupervisory relay U andextinguishing the lamp 27 to notifythe traific yoperator that the printer operator has taken'control of thecircuit. p

The energization of relay H bythe locking keyRSK, as previouslydescribed, opens the circuit previously traced'for the printer operatorslamp 28, but this circuit is reestablished at the same time over thefront contact of the relay G which is now operated. Consequently, thelamp 28 glows as long as the sending circuit is established :tor theprinter. Vihen the sending apparatus of the `printer unit TP is operatedto 'transmit printer sig- ,r nals, the loop TPL is interrupted to causecurrent and' no-current intervals in accordance with the printer code.The receiving' apparatus of the printer units TP and TP record themessagev thus transmitted. At the same time, the transmitting relay TRAor the voice frequency carrier equipment is energire'dland kdeenergizedin accordance with the ycede' to cause an interrupted toneki'rom the`'oscillator Oto be transmitted through the transformer 30 and over thecircuit TCL, cord circuit lCC and two-wire terminal to the .hybridVcoilof vthe four-wire circuit. AFrein the hybrid coil, the teneistransmittedv over the circuit TL through the ley-pass about thc privacymechanismPM, and over the circuit TL to the radio transmitter. At theksame time, ot course,printer signals from the dis'- t-ant station may bereceived through the amplitier-detectorfAD and recorded Von thereceiving printer units RP and RP in the manner previously described.Consequently,

printing may taire place inboth directions at the same time. i Y 1Operation when z/ie printer operator Tegueste a Y j the ycircuit a,

TI". the printer operator desires to use the radio telephone apparatusata time that it is being used 'for voice transmission, she operates therequest service key BSK, causing the operation or relay H as before.Relay il, at its lower front contact, completes a circuitthrough therelay G, outer back left-hand contact or" relay E, back contact of relayD and through the windingA of relay A to batf tery. The operationotrelay A causes the line lamp 25 associated with the jack TCJ to glow,thereby indicating to the traffic operator that the circuit isrequested. -When the trahie operator establishes connection from thecircuit TCL tothe two-wire terminal L by means oi the cord circuit CC,the operation of the relay Din the sleeve circuit releases .relay A andextinguishes the line lamp. 'The other relays operate as previouslydescribed, except that in this inst-ance the relay C is operated by therelay D as soonv as the operator plugs into thejaclr TG5, so that themarginal relay M at once operates and vpr-eventsthe actuation ot thesignal lamp 27 by the supervisory relay U. Y Printing now taires placeas already described. i Y Release of the radio telephone circuit lf thetraffic operator desires to use vthe radio telephone circuit fortelephone transmission Vwithout Waiting for the completion of a printermessage, shepulls down the cord CC connected to the telegraph circuitTCL. This causes therelease of the polari, relay PR associated with thetwo-wire circuit L,.there by restoring' the four-wire circuit to normalcondition, with the transmitting path disabled and the receiving path-innormal talk# ing condition. The relay F associated with thevoicefrequency carrier equipment is also released at the saine time, therebyeXtinguishing the monitoring lamp 27 and the service lamp 28 at theprinter. The printer operator at once kno-ws that the circuit hasy beentakenvaway and simply waits until the circuit. is re-established, which-tact will be indicated by the lamp 28 vagain glowing. II", however, theprinter operator no longer desires to use the circuit, therequest'rservice lrey RSKis restored and the circuit returns to normal.,l n

It the traiiic operator wishes tovuse the cir` cuit for telephonetransmission but iswilling to wait until a telegraph message, then beingsent, is completed, sheV operates the request line key BLK at herposition. lThisconnects interrupted `ground over the contacts of saidoperate and release. VEach timeV the relay B operates, it establishes analternate path for fill BSK, thereby releasing relays G and C.

The latter relay removes the short-circuit from the resistance 1",thereby causing the marginal relay M to release. Consequently,

r the supervisory lamp 27 again glows, giving the traliic operator thesignal to disconnect the sending printer circuit; The operatoraccordingly pulls down the cord' and restores the circuit to normal.

Olonnecz'oa to printer circuit at control board Y It, the attendants inthe control room Wish to' use the radio telephone circuit for printeroperation without involving the traliic operator, the technical operatorconnects the iack CBJ at'the control board to the jack CBJv of thetwo-wire circuit L by means of an ordinary three-conductor patching cordPC. Ground is connected over the sleeve of this cord to operate therelay E. lRelay E transfers the output connection of the transformer 30from the circuit TCLvto the jack CBJ, thus establishing a directconnection to the two-wire circuit L. Relay F and polar relay PR are newoperated, the latter performing the functions previously described.Relay F, however', connects vground over its front contact and makescontact of the outer right board sender of the printer unit TP may beoperated to send messages, it preferred. The

short-circuit previously described as being established over the Contactof relay l does not now exist. It is, of course, obvious that thesending printer TP might be used for sending signals over the circuitthus established.y but the operator of such a printer would not do so,as the lamp 28 would not glow to indicate to such operator that theprinter circuit was established.

Half (Zaple opera-tion The telegraph operations above described were ona full duplex basis, that is, telegraph messages were transmitted fromboth directions at the same time. vhere the circuit is to be operatedo-n a halt duplex basis, so that transmission can take place in bothdirections, but only in one direction at a time, the voice frequencycarrier apparatus will have its circuit modified as shown in Fig. 8.Under these conditions, the receiving loop RCL is disconnected from thevoice frequency carrier apparatus, `and the armature oi' the receivingrelay RR is connected to the neutral point of the transmitting relay TR.llfhen the receiving relay RR is receiving printer signals, positive andnegative batteries are alternately connected to the midpoint of therelaj,T TR, thereby causing current and nocurrent intervals in thetransmitting loop TPL Without actuating the transmitting relay TR.Acordingly, the receiving elements of the printer units TP and TP areoperated to record the received message. Under these conditions, thereceiving printer units BP and RP are not used. lVhen it is desired totransmit from the printer unit TP, for example, the sending apparatus isoperated to open and close the loep TPL. This causes the receivingelements et the units TP and TP to record the message transmitted. Atthe same time, the transmitting relay TR is operated. to send aninterrupted tone from the oscillator C in the manner-previouslydescribed or full duplex operation.

It will be obvious that the general principles herein disclosed may beembodied' in many other organizations widely different from thoseillustrated, Without departing from the spirit of the invention asdetined in the following claims.

` l.What is claimed is:

l. ln a radio telegraph system, a four-wire circuit comprising atransmitting path and a receiving path i''or connecting aradiotransmitter and radio receiver, respectively, to a two-wireterminal, a telegraph transmitter and telegraph receiver, means forcontinuously maintaining said telegraph receiver in connection with saidreceiving path, and means to connect said telegraph transmitter to saidtwo-wire terminal at will.

2. In a radio telegraph system, a four-wire circuit comprising atransmitting path and a receiving path for connecting a radiotransmitter and radio receiver, respectively, to a two-wire terminal, atelegraph transmitter and telegraph receiver, a voice frequency carrierapparatus associated with said telegraph transmitter and receiver, saidapparatus comprising means to translate a received tone into telegraphsignals for said telegraph receiver and means to transmit a tone variedin accordancewith signals 'from said telegraph transmitter, means tomaintain said translating means in continuous connection with saidreceiving path, and means to connect said tone transmitter to saidtwo-wire terminal at will.

lll)

3. ln a radio telegraph system, a vfour-.wire circuit comprisingatransmitting path and a receiving path rorrconnecting a radiotransmitter and a radio receiver, respectively, to a two-wire circuit,an operating room and a controlroom through whichsaid two-wirecircuitpasses, atelegraph transmitter and telegraph receiver in ysaidoperating room, a

telegraph transmitter and telegraph receiver' in said controlroom, meansto maintain said telegraph receivers in continuous connection with saidreceiving path, and means to connect either telegraph.transmitterytosaid twowire circuit atwill.

4. In a radio telephone and telegraph sysmission takes place over theother, a telegraph transmitter and atelegraph receiver, means tomaintain saidtelegraph.receiver continually in connection with saidreceivingv path beyond the point at which it is disabled, means toconnect said telegraph transmitter to said two-wire terminal at will,and means responsive to suchconnection to operate said voice-controlledmeans independently of vocalr transmission to render said transmittingpath continuously operative whilethe connection is established. Y 5.l Ina radio telephone and telegraph system, a tour-wire circuit comprisingVaftransmitting path and a receiving path for connecting a radiotransmitter `and a radio receiver, respectively, to a two-wireterminal,meansto establish telephoneconnections to said two-wire terminal,voice-operated means associated with said tour-wire circuit iFordisabling one ci its paths when telephone transmission takes place overthe other, a telegraph transmitter and a telegraph receiver, a

voice frequency carrier apparatus associated with said telegraphtransmitter and receiver, said apparatus'comprising means to translate areceived tono into telegraph signals for said telegraph receiver andmeans to transmit a tone varied in'accordance with `signals from saidtelegraph transmitter.` means to lmaintain said translating means incontinuous connection with said receiving. path beyond the .point atwhich it is disabled, meanst'o connect said tone transmitter tosaidtwo-wire terminal at will, and means responsive to such connection tooperate said voice-controlled means independently of vocal transmissionto render said transmitting path continuously operative while theconnection is established.

A 6. In a radio telephone and telegraph system, a tour-wire circuit'comprising a transmitting path and a receiving path for conreceiver insaid operating room, a telegraph transmitter and telegraph receiverinsaid control room, means to maintain said telegraph receiverscontinuously connected to said receiving path beyond the point at whichit is disabled, means to connect either telegraph transmitter to saidtwo-wire circuit at. will, and meansV responsive to'such connection ytooperate said voice-controlled meansfindependently of vocal transmissionto render said transmitting path continuously operative while theconnection is established.- Y V '7. In a signaling system, atransmission vcircuit adapted to transmit either telephone or telegraphsignals and terminating at a switching position, a telegraph instrumenthaving a circuitV terminating at said switching position, a telephoneline terminating' at said switchingv position, means vat said switchingposition whereby a traffic operator may connect said telegraphinstrument or said telephone line to saidy transmission circuita't'will, and means operative when the telegraph instrument lisVdisconnected Jfrom the transmission circuit whereby the telegraphoperator may indicate to the traiiic Voperator that a connection 'isdesired. v Y

l 8. ln a `signaling system,y -a transmission circuit adapted totransmit either telephone or telegraph signals and terminating at aswitching position, a telegraph instrument having a circuit terminatingat said switching position, a telephone line terminating at saidswitching positiommeans at said switching'v Aposition whereby a traiiicoperator may connect said telegraph instrument or said telephone line tosaid transmission circuit at will, and means independent oi' theoperators telegraph instrument to indicate to the telegraph Voperatorthat the telegraph instrument has been connected at the switchingposition. l l

9. In a signaling system, a transmission circuit adapted to transmiteither telephone or telegraph signals and terminating at a Vswitchingposition, a telegraph instrument link circuit to indicate to the traiicoperator that the telegraph operator desires the connection between thetelegraph instrument and the transmission circuit taken down.

l0. In a signaling system, a transmission circuit adapted to transmiteither telephone or telegraph signals and terminating at a switchingposition, a telegraph instrument having a circuit terminating at saidswitching position, a telephone line terminating at said switchingposition, means at said switching position whereby a traiiic operatormay connect said telegraph instrument or said telephone line to saidtransmission circuit at will, means operative when the telegraphinstrument is disconnected from the transmission circuit whereby thetelegraph operator may indicate to the trailic operator that aconnection is desired, means independent of the operators telegraphinstrument to indicate to the telegraph operator that the telegraphinstrument has been connected at the switching position, and means atthe switching position to indicate to the traiic operator that thetelegraph operator desires the connections taken down.

11. In a signaling system, a transmission circuit adapted to transmiteither telephone or telegraph signals and terminating at a switchingposition, a telegraph instrument having a circuit terminating at saidswitching position, a telephone line terminating at said switchingposition, means at said switching position whereby a traiiic operatormay connect said telegraph instrument or said telephone line to saidtransmission circuit at will, and means independent of the operatorstelegraph instrument to indicate to the telegraph operator during thecontinuance of an established connection from the telegraph instrumentto the transmission circuit that the trattic operator desires to takedown the connection.

12. In a radio telephone and telegraph system, a four-wire circuitcomprising a transmitting path and a receiving path Jfor connecting aradio transmitter and a radio receiver, respectively, to a two-wireterminal, means to establish telephone connections to said two-wireterminal, voice-operated means associated with said four-wire circuitfor disabling one of its paths when telephone transmission takes placeover the other, an amplier in said transmission path, a privacymechanism associated with said four-wire circuit for rendering speechunintelligible, a telegraph transmitter and a telegraph receiver, meansto maintain said telegraph receiver continuously in connection with saidreceiving path beyond the point at which it is disabled, means toconnect said telegraph transmitter to said two-wire terminal at will,means responsive to such connection to set the gain of said amplifier ata predetermined level, to cut out said privacy mechanism, and

